Sintering machine pallet and grate bar



H. K. NAJARIAN SINTERING MACHINE PALLET AND GRATE BAR Filed Feb. 12, 1952 gwuantot H 7 41 Nov. 29, 1932.

Patented Nov. 29, 1932 UNITED STAT HERAND K. NAJ'ARIAN, v

COMPANY, OF NEW YORK,

ES PATENT OFFICE or BEAVER, PENNSYLVANIA, ASSIGNOR 'ro JOSEPH LEAD N. Y.,- A CORPORATION OF NEW YORK SINTERING MACHINE PALLET. AND GRATE BAR Application filed February 12, 1932. Serial No. 592,609.

This invention relates to sintering machines of the well known Dwight and Lloyd type and particularly to an improved grate bar assembly applicable to the pallets or cars used in conjunction with said type of sinter:

Various types of grate bars are used on the cars or pallets of this type of sintering machines, some of the grate bars being placed on the cars parallel to the line of travel of the pallets and others at right angles thereto. This invention is directed to a form of construction in which the grate bars are placed on the pallets at right angles to the line of travel ofthe pallets.

Most of the commercial sintering machines found in industrial plants employ pallets from 3 feet to 6 feet in width, the grate bars of various forms being placed on ledges on two side members of the pallets and held down with holding bars at both ends. As the material to be sintered on these machines is usually fine crushed material it is necessary that the openings between the grate bars serving as air passages be relatively small. At the same time it is very desirable to have a proportionately large air passage area to permit the necessary amount of air to be drawn through the mass of material being sintered, making it necessary for the grate bars to be as narrow as possible. But as the grate bars are subjected to alternate heating and cooling and also to considerable impact, a narrow and long grate bar such as is commonly used soon becomes warped and bent. Consequently if the grate bars are made shorter and narrower, with proportionately more air passage area, the efficiency of the machine is increased and the grate bars will have less tendency to warp and bend.

My invention provides a grate bar assembly in which the grate bars are short and narrow and free from projecting lugs, in which the ends of the bars are protected from excessive heat and in which the bars are maintained in alignment without subjecting the bars to strain and without permitting excessive movement and impacts of the bars.

The invention will be more particularly described with reference to the accompanying drawing in which:

Fig. 1 is a plan view of the grate bar assembly, partially broken away to show the pallet construction Fig. 2 is a section on line 22 of Fig. 1;

Fig. 3 is a section on line 33 of Fig. 1; and

Fig. 4 is a perspective view of the grate bar of the invention.

In the drawing, 1 is the frame of the pallet or car, having a central bracing member 2 and cross bracing members 3. The grate bars 4 are arranged in two parallel rows, the outer ends of the bars in each row resting on a ledge in the sides of the pallet frame,

and the inner ends of the bars in each row resting in horizontal slots cut in a central holding bar 5 resting on member 2 and fastened thereto by means of bolts and nuts 6.

The rate bars are held in position by means.

of lateral holding bars 7 fastened to the side members of the pallet frame by bolts and nuts 8.

The grate bars 4, as shown more particularly in Fig. 4, are relatively short narrow bars, having vertically semi-cylindrical ends. Shoulders 9 at the ends and along the sides of the bars provide the proper spacing of the bars for the passage of air. The bars are preferably so proportioned that the percentage of air space referred to the whole pallet area may be between 13 and 15%. The semicylindrical ends fit into semi-circular grooves in the lateral and central holding bars. To remove or replace a gratebar, the lateral holding bar 7 is unfastened and removed and the grate bar is rotated upward about its inner end. All of the bars are identical in form except the end bar and any bar may be quickly removed and replaced without moving the other bars or interfering with the operation those forms in which the bars of the sintering machine, the replacement of bars being advantageously eflected as the pallet rises over the driving wheel prior to the feeding of the charge thereon.

The grate bar assembly described herein possesses certain very material advantages over the forms in which the grate bars extend across the whole width of the pallet and over are positioned longitudinally to the pallet. The principal advantages over the former are the greater life of the bars and their greater freedom from warping and ease of replacement. 7

The forms in which the bars are positioned longitudinally to the pallet suffer from the disadvantage that the end lugs tend to wear and burn away rapidly thus reducing the width of air passages between the grate bars. In those forms in which the bars are held in place by a transverse locking bar, the latter is a source of trouble because of the interference with the proper sintering of the charge in its vicinity. These disadvantages are avoided by the grate bar assembly of the invention.

Another advantage of the invention is the I provision made for causing the sinter cake to readily break into smaller pieces. This is effected by shaping the upper portion of the central holding bar 5 so as to produce a line of weakness 10 in the sinter cake. This form of holding bar also tends to produce a more uniform distribution of the draft in its vicinity and to-avoid the production of any areas of improperly sintered material.

Since the grate bars are loosely held on the pallet and are at right angles to the line of travel of the pallets they may be efliciently cleaned by the rapper mechanism shown in copending application Serial No. 539,912.

The invention is not limited to the particular form illustrated herein by way of example and many changes may be made without departing from the spirit of the invention which broadly comprises a pallet and grate bar assembly including a frame having two parallel rows of grate bars positioned thereon at right angles to the direction of travel of the pallet and held in place by a central member and by lateral holding members removably attached to the sides of the frame.

The central holding member need not be removable butmay if desired be integral with the pallet frame. In the case of very wide pallets it might be desirable to use more than two rows of grate bars, in which case the bars of the inner rows could be replaced by removing one of the central holding bars. Other obvious possible variations will occur to those skilled in the art.

What I claim is 1. A pallet for sintering machines comprising a frame, a plurality of grate bars posi tioned on said frame transversely to the direction of travel of the pallet and in two parallel rows, a central member adapted to retain the inner ends of the bars of said rows and lateral members removably attached to the sides of said frame adapted to retain the outer ends of the bars.

2. A pallet for sintering machines comprising a frame, a plurality of grate bars positioned on said frame transversely to the direction of travel of the pallet and in a plurality of parallel rows, a removable central member adapted to retain the inner ends of the bars of said rows and lateral members removably attached. to the sides of said frame adapted to retain the outer'ends of the bars.

3. In sintering machines, a pallet comprising a frame supporting grate bars, a central longitudinal retaining member and removable lateral retaining members, said lateral members when 1n position on sa1d frame cooperating with said central member to hold in alignment on said frame two parallel rows of transversely positioned grate bars.

4. In sintering machines, a pallet comprising a frame supporting grate bars, a removable central longitudinal retain ng member and removable lateral retaining members, said lateral members when in position on said frame cooperating with said central member to hold in alignment on said frame two parallel rows of transversely positioned grate bars.

5. A pallet for sinter'ng machines having a frame, a plurality of grate bars transversely positioned thereon in at least two parallel rows, removable lateral retaining members, and at least one central longitudinal retaining member.

6. A pallet for sintering machines having a frame, a plurality of grate bars transversely positioned thereon in at least two parallel rows, removable lateral reta ning members, and at least one central longitudinal retaining member shaped to produce a longitudinal plane of weakness in the sinter cake.

7. A pallet for sintering machines having a frame, a plurality of grate bars transversely positioned thereon in at least two parallel rows, removable lateral retaining mem bers, and at least one central longitudinal retaining member projecting in the form of a wedge into the lower portion of the charge.

8. A grate bar for sintering machines and the like characterized by substantially semicylindrical transverse ends, and by being symmetrical with respect to both its vertical median planes.

9. A grate bar for sintering machines and the like having an elongated principal por tion of trapezoidal section and transverse semicylindrical end portions.

10. A grate bar as defined in claim 9 having spacing shoulders positioned on the nonparallel faces of the principal portion.

In testimony whereof, I afiiX my signature. 

